+++ /dev/null
-/*
- * SCSI device handler infrastruture.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright IBM Corporation, 2007
- * Authors:
- * Chandra Seetharaman <sekharan@us.ibm.com>
- * Mike Anderson <andmike@linux.vnet.ibm.com>
- */
-
-#include <linux/slab.h>
-#include <linux/module.h>
-#include <scsi/scsi_dh.h>
-#include "../scsi_priv.h"
-
-static DEFINE_SPINLOCK(list_lock);
-static LIST_HEAD(scsi_dh_list);
-
-static struct scsi_device_handler *get_device_handler(const char *name)
-{
- struct scsi_device_handler *tmp, *found = NULL;
-
- spin_lock(&list_lock);
- list_for_each_entry(tmp, &scsi_dh_list, list) {
- if (!strncmp(tmp->name, name, strlen(tmp->name))) {
- found = tmp;
- break;
- }
- }
- spin_unlock(&list_lock);
- return found;
-}
-
-/*
- * device_handler_match_function - Match a device handler to a device
- * @sdev - SCSI device to be tested
- *
- * Tests @sdev against the match function of all registered device_handler.
- * Returns the found device handler or NULL if not found.
- */
-static struct scsi_device_handler *
-device_handler_match_function(struct scsi_device *sdev)
-{
- struct scsi_device_handler *tmp_dh, *found_dh = NULL;
-
- spin_lock(&list_lock);
- list_for_each_entry(tmp_dh, &scsi_dh_list, list) {
- if (tmp_dh->match && tmp_dh->match(sdev)) {
- found_dh = tmp_dh;
- break;
- }
- }
- spin_unlock(&list_lock);
- return found_dh;
-}
-
-/*
- * device_handler_match - Attach a device handler to a device
- * @scsi_dh - The device handler to match against or NULL
- * @sdev - SCSI device to be tested against @scsi_dh
- *
- * Tests @sdev against the device handler @scsi_dh or against
- * all registered device_handler if @scsi_dh == NULL.
- * Returns the found device handler or NULL if not found.
- */
-static struct scsi_device_handler *
-device_handler_match(struct scsi_device_handler *scsi_dh,
- struct scsi_device *sdev)
-{
- struct scsi_device_handler *found_dh;
-
- found_dh = device_handler_match_function(sdev);
-
- if (scsi_dh && found_dh != scsi_dh)
- found_dh = NULL;
-
- return found_dh;
-}
-
-/*
- * scsi_dh_handler_attach - Attach a device handler to a device
- * @sdev - SCSI device the device handler should attach to
- * @scsi_dh - The device handler to attach
- */
-static int scsi_dh_handler_attach(struct scsi_device *sdev,
- struct scsi_device_handler *scsi_dh)
-{
- struct scsi_dh_data *d;
-
- if (sdev->scsi_dh_data) {
- if (sdev->scsi_dh_data->scsi_dh != scsi_dh)
- return -EBUSY;
-
- kref_get(&sdev->scsi_dh_data->kref);
- return 0;
- }
-
- if (!try_module_get(scsi_dh->module))
- return -EINVAL;
-
- d = scsi_dh->attach(sdev);
- if (IS_ERR(d)) {
- sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%ld)\n",
- scsi_dh->name, PTR_ERR(d));
- module_put(scsi_dh->module);
- return PTR_ERR(d);
- }
-
- d->scsi_dh = scsi_dh;
- kref_init(&d->kref);
- d->sdev = sdev;
-
- spin_lock_irq(sdev->request_queue->queue_lock);
- sdev->scsi_dh_data = d;
- spin_unlock_irq(sdev->request_queue->queue_lock);
- return 0;
-}
-
-static void __detach_handler (struct kref *kref)
-{
- struct scsi_dh_data *scsi_dh_data =
- container_of(kref, struct scsi_dh_data, kref);
- struct scsi_device_handler *scsi_dh = scsi_dh_data->scsi_dh;
- struct scsi_device *sdev = scsi_dh_data->sdev;
-
- scsi_dh->detach(sdev);
-
- spin_lock_irq(sdev->request_queue->queue_lock);
- sdev->scsi_dh_data = NULL;
- spin_unlock_irq(sdev->request_queue->queue_lock);
-
- sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", scsi_dh->name);
- module_put(scsi_dh->module);
-}
-
-/*
- * scsi_dh_handler_detach - Detach a device handler from a device
- * @sdev - SCSI device the device handler should be detached from
- * @scsi_dh - Device handler to be detached
- *
- * Detach from a device handler. If a device handler is specified,
- * only detach if the currently attached handler matches @scsi_dh.
- */
-static void scsi_dh_handler_detach(struct scsi_device *sdev,
- struct scsi_device_handler *scsi_dh)
-{
- if (!sdev->scsi_dh_data)
- return;
-
- if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh)
- return;
-
- if (!scsi_dh)
- scsi_dh = sdev->scsi_dh_data->scsi_dh;
-
- if (scsi_dh)
- kref_put(&sdev->scsi_dh_data->kref, __detach_handler);
-}
-
-/*
- * Functions for sysfs attribute 'dh_state'
- */
-static ssize_t
-store_dh_state(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct scsi_device *sdev = to_scsi_device(dev);
- struct scsi_device_handler *scsi_dh;
- int err = -EINVAL;
-
- if (sdev->sdev_state == SDEV_CANCEL ||
- sdev->sdev_state == SDEV_DEL)
- return -ENODEV;
-
- if (!sdev->scsi_dh_data) {
- /*
- * Attach to a device handler
- */
- if (!(scsi_dh = get_device_handler(buf)))
- return err;
- err = scsi_dh_handler_attach(sdev, scsi_dh);
- } else {
- scsi_dh = sdev->scsi_dh_data->scsi_dh;
- if (!strncmp(buf, "detach", 6)) {
- /*
- * Detach from a device handler
- */
- scsi_dh_handler_detach(sdev, scsi_dh);
- err = 0;
- } else if (!strncmp(buf, "activate", 8)) {
- /*
- * Activate a device handler
- */
- if (scsi_dh->activate)
- err = scsi_dh->activate(sdev, NULL, NULL);
- else
- err = 0;
- }
- }
-
- return err<0?err:count;
-}
-
-static ssize_t
-show_dh_state(struct device *dev, struct device_attribute *attr, char *buf)
-{
- struct scsi_device *sdev = to_scsi_device(dev);
-
- if (!sdev->scsi_dh_data)
- return snprintf(buf, 20, "detached\n");
-
- return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name);
-}
-
-static struct device_attribute scsi_dh_state_attr =
- __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
- store_dh_state);
-
-/*
- * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh
- */
-static int scsi_dh_sysfs_attr_add(struct device *dev, void *data)
-{
- struct scsi_device *sdev;
- int err;
-
- if (!scsi_is_sdev_device(dev))
- return 0;
-
- sdev = to_scsi_device(dev);
-
- err = device_create_file(&sdev->sdev_gendev,
- &scsi_dh_state_attr);
-
- return 0;
-}
-
-/*
- * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh
- */
-static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data)
-{
- struct scsi_device *sdev;
-
- if (!scsi_is_sdev_device(dev))
- return 0;
-
- sdev = to_scsi_device(dev);
-
- device_remove_file(&sdev->sdev_gendev,
- &scsi_dh_state_attr);
-
- return 0;
-}
-
-/*
- * scsi_dh_notifier - notifier chain callback
- */
-static int scsi_dh_notifier(struct notifier_block *nb,
- unsigned long action, void *data)
-{
- struct device *dev = data;
- struct scsi_device *sdev;
- int err = 0;
- struct scsi_device_handler *devinfo = NULL;
-
- if (!scsi_is_sdev_device(dev))
- return 0;
-
- sdev = to_scsi_device(dev);
-
- if (action == BUS_NOTIFY_ADD_DEVICE) {
- err = device_create_file(dev, &scsi_dh_state_attr);
- /* don't care about err */
- devinfo = device_handler_match(NULL, sdev);
- if (devinfo)
- err = scsi_dh_handler_attach(sdev, devinfo);
- } else if (action == BUS_NOTIFY_DEL_DEVICE) {
- device_remove_file(dev, &scsi_dh_state_attr);
- scsi_dh_handler_detach(sdev, NULL);
- }
- return err;
-}
-
-/*
- * scsi_dh_notifier_add - Callback for scsi_register_device_handler
- */
-static int scsi_dh_notifier_add(struct device *dev, void *data)
-{
- struct scsi_device_handler *scsi_dh = data;
- struct scsi_device *sdev;
-
- if (!scsi_is_sdev_device(dev))
- return 0;
-
- if (!get_device(dev))
- return 0;
-
- sdev = to_scsi_device(dev);
-
- if (device_handler_match(scsi_dh, sdev))
- scsi_dh_handler_attach(sdev, scsi_dh);
-
- put_device(dev);
-
- return 0;
-}
-
-/*
- * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler
- */
-static int scsi_dh_notifier_remove(struct device *dev, void *data)
-{
- struct scsi_device_handler *scsi_dh = data;
- struct scsi_device *sdev;
-
- if (!scsi_is_sdev_device(dev))
- return 0;
-
- if (!get_device(dev))
- return 0;
-
- sdev = to_scsi_device(dev);
-
- scsi_dh_handler_detach(sdev, scsi_dh);
-
- put_device(dev);
-
- return 0;
-}
-
-/*
- * scsi_register_device_handler - register a device handler personality
- * module.
- * @scsi_dh - device handler to be registered.
- *
- * Returns 0 on success, -EBUSY if handler already registered.
- */
-int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
-{
-
- if (get_device_handler(scsi_dh->name))
- return -EBUSY;
-
- if (!scsi_dh->attach || !scsi_dh->detach)
- return -EINVAL;
-
- spin_lock(&list_lock);
- list_add(&scsi_dh->list, &scsi_dh_list);
- spin_unlock(&list_lock);
-
- bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add);
- printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
-
- return SCSI_DH_OK;
-}
-EXPORT_SYMBOL_GPL(scsi_register_device_handler);
-
-/*
- * scsi_unregister_device_handler - register a device handler personality
- * module.
- * @scsi_dh - device handler to be unregistered.
- *
- * Returns 0 on success, -ENODEV if handler not registered.
- */
-int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
-{
-
- if (!get_device_handler(scsi_dh->name))
- return -ENODEV;
-
- bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh,
- scsi_dh_notifier_remove);
-
- spin_lock(&list_lock);
- list_del(&scsi_dh->list);
- spin_unlock(&list_lock);
- printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
-
- return SCSI_DH_OK;
-}
-EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
-
-/*
- * scsi_dh_activate - activate the path associated with the scsi_device
- * corresponding to the given request queue.
- * Returns immediately without waiting for activation to be completed.
- * @q - Request queue that is associated with the scsi_device to be
- * activated.
- * @fn - Function to be called upon completion of the activation.
- * Function fn is called with data (below) and the error code.
- * Function fn may be called from the same calling context. So,
- * do not hold the lock in the caller which may be needed in fn.
- * @data - data passed to the function fn upon completion.
- *
- */
-int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
-{
- int err = 0;
- unsigned long flags;
- struct scsi_device *sdev;
- struct scsi_device_handler *scsi_dh = NULL;
- struct device *dev = NULL;
-
- spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
- if (!sdev) {
- spin_unlock_irqrestore(q->queue_lock, flags);
- err = SCSI_DH_NOSYS;
- if (fn)
- fn(data, err);
- return err;
- }
-
- if (sdev->scsi_dh_data)
- scsi_dh = sdev->scsi_dh_data->scsi_dh;
- dev = get_device(&sdev->sdev_gendev);
- if (!scsi_dh || !dev ||
- sdev->sdev_state == SDEV_CANCEL ||
- sdev->sdev_state == SDEV_DEL)
- err = SCSI_DH_NOSYS;
- if (sdev->sdev_state == SDEV_OFFLINE)
- err = SCSI_DH_DEV_OFFLINED;
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- if (err) {
- if (fn)
- fn(data, err);
- goto out;
- }
-
- if (scsi_dh->activate)
- err = scsi_dh->activate(sdev, fn, data);
-out:
- put_device(dev);
- return err;
-}
-EXPORT_SYMBOL_GPL(scsi_dh_activate);
-
-/*
- * scsi_dh_set_params - set the parameters for the device as per the
- * string specified in params.
- * @q - Request queue that is associated with the scsi_device for
- * which the parameters to be set.
- * @params - parameters in the following format
- * "no_of_params\0param1\0param2\0param3\0...\0"
- * for example, string for 2 parameters with value 10 and 21
- * is specified as "2\010\021\0".
- */
-int scsi_dh_set_params(struct request_queue *q, const char *params)
-{
- int err = -SCSI_DH_NOSYS;
- unsigned long flags;
- struct scsi_device *sdev;
- struct scsi_device_handler *scsi_dh = NULL;
-
- spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
- if (sdev && sdev->scsi_dh_data)
- scsi_dh = sdev->scsi_dh_data->scsi_dh;
- if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev))
- err = 0;
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- if (err)
- return err;
- err = scsi_dh->set_params(sdev, params);
- put_device(&sdev->sdev_gendev);
- return err;
-}
-EXPORT_SYMBOL_GPL(scsi_dh_set_params);
-
-/*
- * scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for
- * the given name. FALSE(0) otherwise.
- * @name - name of the device handler.
- */
-int scsi_dh_handler_exist(const char *name)
-{
- return (get_device_handler(name) != NULL);
-}
-EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
-
-/*
- * scsi_dh_attach - Attach device handler
- * @q - Request queue that is associated with the scsi_device
- * the handler should be attached to
- * @name - name of the handler to attach
- */
-int scsi_dh_attach(struct request_queue *q, const char *name)
-{
- unsigned long flags;
- struct scsi_device *sdev;
- struct scsi_device_handler *scsi_dh;
- int err = 0;
-
- scsi_dh = get_device_handler(name);
- if (!scsi_dh)
- return -EINVAL;
-
- spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
- if (!sdev || !get_device(&sdev->sdev_gendev))
- err = -ENODEV;
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- if (!err) {
- err = scsi_dh_handler_attach(sdev, scsi_dh);
- put_device(&sdev->sdev_gendev);
- }
- return err;
-}
-EXPORT_SYMBOL_GPL(scsi_dh_attach);
-
-/*
- * scsi_dh_detach - Detach device handler
- * @q - Request queue that is associated with the scsi_device
- * the handler should be detached from
- *
- * This function will detach the device handler only
- * if the sdev is not part of the internal list, ie
- * if it has been attached manually.
- */
-void scsi_dh_detach(struct request_queue *q)
-{
- unsigned long flags;
- struct scsi_device *sdev;
- struct scsi_device_handler *scsi_dh = NULL;
-
- spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
- if (!sdev || !get_device(&sdev->sdev_gendev))
- sdev = NULL;
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- if (!sdev)
- return;
-
- if (sdev->scsi_dh_data) {
- scsi_dh = sdev->scsi_dh_data->scsi_dh;
- scsi_dh_handler_detach(sdev, scsi_dh);
- }
- put_device(&sdev->sdev_gendev);
-}
-EXPORT_SYMBOL_GPL(scsi_dh_detach);
-
-/*
- * scsi_dh_attached_handler_name - Get attached device handler's name
- * @q - Request queue that is associated with the scsi_device
- * that may have a device handler attached
- * @gfp - the GFP mask used in the kmalloc() call when allocating memory
- *
- * Returns name of attached handler, NULL if no handler is attached.
- * Caller must take care to free the returned string.
- */
-const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
-{
- unsigned long flags;
- struct scsi_device *sdev;
- const char *handler_name = NULL;
-
- spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
- if (!sdev || !get_device(&sdev->sdev_gendev))
- sdev = NULL;
- spin_unlock_irqrestore(q->queue_lock, flags);
-
- if (!sdev)
- return NULL;
-
- if (sdev->scsi_dh_data)
- handler_name = kstrdup(sdev->scsi_dh_data->scsi_dh->name, gfp);
-
- put_device(&sdev->sdev_gendev);
- return handler_name;
-}
-EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
-
-static struct notifier_block scsi_dh_nb = {
- .notifier_call = scsi_dh_notifier
-};
-
-static int __init scsi_dh_init(void)
-{
- int r;
-
- r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb);
-
- if (!r)
- bus_for_each_dev(&scsi_bus_type, NULL, NULL,
- scsi_dh_sysfs_attr_add);
-
- return r;
-}
-
-static void __exit scsi_dh_exit(void)
-{
- bus_for_each_dev(&scsi_bus_type, NULL, NULL,
- scsi_dh_sysfs_attr_remove);
- bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb);
-}
-
-module_init(scsi_dh_init);
-module_exit(scsi_dh_exit);
-
-MODULE_DESCRIPTION("SCSI device handler");
-MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>");
-MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff